In the past, ketones has been converted to epoxides with sulphonic ylides. See Corey, et al. (J. Am. Chem. Soc. 87, 1353; and House, Modern Synthetic Reactions, Second Ed. W. A. Benjamin, Inc., Menlo Park, Calif., pg. 717, 1972. While this process has been utilized to epoxidize ketones, it has not been applied to polyene unsaturated ketones containing an unsaturation at the .alpha.,.beta. position. Nor has this been applied to a process for producing .alpha.,.beta.-unsaturated polyene aldehydes by homologation of aldehydes or ketones.
The .alpha.,.beta. -unsaturated polyene aldehydes are very important compounds owing to their use as intermediates in the preparation of vitamins, carotenoids, and odor imparting compounds. However, the synthesis of these materials has met with some difficulty due to low yields and contaminating side products. As reported by Thomas, on page 52 of Terpenoids and Steroids, Specialist Periodical Reports, Vol. 3, published by Chemical Society, Burlington House, London, England, a good synthesis for .alpha.,.beta.-unsaturated aldehydes such as .beta.-cyclocitral "is indeed desired".
In the past, the major method for synthesizing .alpha.,.beta. -unsaturated polyene aldehydes has been from lower polyene, .alpha.,.beta. -unsaturated aldehydes or ketones by the Darzens reaction. See Isler, Carotenoids, Birkhauser Verlag, Basel and Stuttgart pp. 344-545. However, this process has suffered from the disadvantage that the yields are relatively poor especially after being carried out in large scale production. Therefore, a more efficient method for producing an .alpha.,.beta. -unsaturated polyene aldehyde from lower .alpha.,.beta.-unsaturated polyene aldehydes has long been desired in the art.